Gibson (1-2), who signed with Texas in the offseason after spending the first 10 years of his career with Minnesota, went 6 1/3 innings and allowed two runs on seven hits. He struck out two and walked one in his first career appearance against the Rockies.

Rafael Montero worked the ninth for his fifth save, allowing an unearned run after leadoff man Raimel Tapia reached on catcher’s interference.

Dietrich, who hit a career-high 19 home runs for Cincinnati last season, joined the Rangers on a minor league deal Monday after being released by the Chicago Cubs a week ago. He was signed to a major league contract Tuesday and activated by the Rangers and has been making an impact ever since.

“I think it has a lot to do with my routine and my preparation,” Dietrich said. “I prepare the same way each and every day. I did it all offseason, did it during the in between time. … The most successful hitters I’ve been around, stick to their routine and trust it.

“I’ve played baseball a long time, it’s just rolling now.”

In the eighth, he hit the first pitch he saw from Carlos Estevez, driving it the opposite way into the left field bleachers for his first homer with the Rangers.

The Rockies broke on top on Wolters’ two-run double in the second inning but the Rangers generated plenty of baserunners against German Marquez (2-3) and managed to chip away at the lead despite a Colorado defense that turned three double plays.